Stuart Tyrer, 55, contracted the virus at Telford’s Princess Royal Hospital more than a month ago while being treated for a blood clot to the lung. He has also been suffering from pneumonia, and has been in intensive care since Christmas.
Since then he has suffered pneumonia and a blood clot to the lung, and has been in intensive care since Christmas.
Earlier this month he was placed on a ventilator, and has been placed in an induced coma.
Friend Andy McCauley, chairman of West Mercia Search and Rescue, said Stuart had been a volunteer with the group for more than a decade.
Last year he was presented with a civic award from the Mayor of Wellington for his work for the charity, which has its head office in Tipton. He was also a runner-up in the Shropshire Star's 2015 Pride of Shropshire awards.
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Stuart, who lives in Leegomery, Telford, is trained in rescuing people from caves, rivers and mountains.
He took part in the search for five-year-old April Jones when she went missing from her home in October 2012.
Stuart was also the voluntary first aider at Wellington Market, where he has a blind and curtain stall.
Andy said Stuart had come close to losing his life at one stage, but appeared to be showing signs of recovery, although it will be a while before he will be able to return to work.
"He was a young, healthy strong man, it just shows how anybody can be affected by the coronavirus.
"This nasty news strain in particular seems to be taking people of all ages."
Andy said Stuart, who is married to Jane, had been without any income since the lockdown forced him to temporarily close his market stall last year.
More than £9,000 has been raised by well-wishers so that Stuart will be able to support himself when he recovers from his illness.
"He's a gentleman, caring and unassuming," said Andy.
"He's always positive and would give his last pound to anyone in need."
Andy said Stuart's illness would mean a long recuperation period.
"We don't imagine he'll be able to work for quite some time, maybe months," he said.
"We don't want him to force himself back to work early and do more damage just because money becomes a struggle."
Anybody wanting to donate to the fund can do so through the website justgiving.com/crowdfunding/cavey